Thymosin α1 is a native peptide in several tissues

Franco, Francisco; Dı́az, Cristina; Barcia, Miguel González; Freire, Manuel

doi:10.1016/0167-4838(92)90422-a

Cited by 36 publications

(23 citation statements)

References 17 publications

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“…This led to the suggestion that the presence of ProT␣-derived ␣-thymosins in TF5 was an artifact resulting from uncontrolled proteolysis during preparation of TF5. In contrast, experiments performed in our laboratory, using isoelectric focusing rather than HPLC for ␣-thymosin detection, have indicated that T␣ 1 is indeed present in extracts of this type in diverse mammalian tissues (10).…”

mentioning

confidence: 74%

“…Obtention of ␣-Thymosins-A heat-stable acidic polypeptide fraction (including the ␣-thymosins) was obtained from whole cell extracts or from subcellular fractions by a modification of the procedure of Goldstein et al (1), as previously described (10). Briefly, frozen cells or subcellular fractions were pulverized under liquid nitrogen with a chilled pestle and mortar, dispersed in 10 volumes of boiling 0.15 M NaCl, and homogenized in a Waring blender.…”

Section: Methodsmentioning

confidence: 99%

“…Isoelectrofocusing and SDS-PAGE-Isoelectrofocusing was carried out as described previously (10). Briefly, samples were applied to PAG plates with a pH range of 4.0 -6.5 (Amersham Biosciences) and electrofocused for 2.5 h (2000 V, 25 mA, 25 watts) in a LKB Multiphor isoelectric focusing cell thermostatted at 10°C.…”

Section: Methodsmentioning

confidence: 99%

“…This apparent precursor of the ␣-thymosins was later isolated from thymus (8) and other mammalian tissues (9,10). Sequencing indicated that it comprised 109 -111 amino acids, including the sequence of T␣ 11 (and thus T␣ 1 ) at its N terminus (11,12).…”

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confidence: 99%

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Prothymosin α Is Processed to Thymosin α1 and Thymosin α11 by a Lysosomal Asparaginyl Endopeptidase

Sarandeses

Covelo

Díaz-Jullien

et al. 2003

Journal of Biological Chemistry

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Thymosin ␣ 1 (T␣ 1 ) and thymosin T␣ 11 (T␣ 11 ) are polypeptides with immunoregulatory properties first isolated from thymic extracts, corresponding to the first 28 and 35 amino acid residues, respectively, of prothymosin ␣ (ProT␣), a protein involved in chromatin remodeling. It has been widely supposed that these polypeptides are not natural products of the in vivo processing of ProT␣, since neither was found in extracts in which proteolysis was prevented. Here we show that a lysosomal asparaginyl endopeptidase is able to process ProT␣ to generate T␣ 1 and T␣ 11 . In view of its catalytic properties and structural and immunological analyses, this protease was identified as mammalian legumain. It selectively cleaves some of the asparaginylglycine residues in the ProT␣ sequence; specifically, Asn 28 -Gly 29 and Asn 35 -Gly 36 residues are cleaved with similar efficiency in vitro to generate T␣ 1 and T␣ 11 , respectively. By contrast T␣ 1 is the main product detected in vivo, free in the cytosol, at concentrations similar to that of ProT␣. The data here reported demonstrate that T␣ 1 is not an artifact but rather is naturally present in diverse mammalian tissues and raise the possibility that it has a functional role.

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confidence: 74%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Prothymosin α Is Processed to Thymosin α1 and Thymosin α11 by a Lysosomal Asparaginyl Endopeptidase

Sarandeses

Covelo

Díaz-Jullien

et al. 2003

Journal of Biological Chemistry

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“…Antibodies to human casein kinase II were obtained from Upstate Biotechnology Inc. and casein kinase II from Promega. ProT␣ was purified from calf thymocytes as described (10). All other reagents and materials were of analytical grade.…”

Section: Methodsmentioning

confidence: 99%

A 180-kDa Protein Kinase Seems to Be Responsible for the Phosphorylation of Prothymosin α Observed in Proliferating Cells

Pérez-Estévez

Díaz-Jullien

Covelo

et al. 1997

Journal of Biological Chemistry

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Prothymosin ␣ (ProT␣) is an acidic protein involved in cell proliferation. Its phosphorylation status is correlated with proliferative activity. Here we report the isolation and characterization of a ProT␣-phosphorylating kinase (ProT␣K) from mouse splenocytes that seems to be responsible for the in vivo phosphorylation of ProT␣ and that differs from other protein kinases reported to date. This enzyme, mainly located in the cytosol, has an molecular mass of 180 kDa and appears to be made up of two proteins of 64 and 60 kDa. Its activity was markedly enhanced by mitogenic activation of cells. The ProT␣ residues phosphorylated by the enzyme in vitro are a Thr at position 7 and another Thr at positions 12 or 13, both located within casein kinase 2 (CK-2) consensus motifs; these are the same residues as are phosphorylated in vivo. The new enzyme shows a number of clear structural and catalytic differences from CK-2. It phosphorylates histones H2B and H3, although with weaker activity than ProT␣. An enzyme with the same characteristics was also found in other murine tissues and cell lines.

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New studies about the insertion mechanism of Thymosin α1 in negative regions of model membranes as starting point of the bioactivity

et al. 2016

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Thymosin α1 is a peptidic hormone already used in the therapy of several diseases. Until now, the description of the precise receptor and mechanism for its action still remains elusive. The interaction of Thymosin α1, which is unstructured in water solution, has been recently studied in sodium dodecylsulphate micellar systems and it was reported that Thymosin α1 inserts in micelle assuming a conformation with two tracts of helix with a structural break in between. An investigation of its interaction both with micelles of dodecylphosphocholine alone and with mixed dodecylphosphocholine-sodium dodecylsulphate micelles is here reported. In these environments the results indicate that Thymosin α1 in phospholipidic membrane exposing choline polar heads interacts by aspecific modality and, oppositely, in the mixed dodecylphosphocholine-sodium dodecylsulphate micelles an insertion in the micellar hydrophobic region conformationally similar to that found in sodium dodecylsulphate micelles occurs. In presence of mixed micelles the insertion and structuration occur in preferred regions when the membrane models are negatively charged. From the point of view of the mechanism of action, insertion its N terminus in negative regions of membrane led to hypothesize that this process would be similar to a binding to phosphatidylserine exposed like in apoptotic cells. Thymosin α1 when inserted may interact with nearby proteins and/or receptors acting as effector and causing a biological signaling cascade. The recent attention to the phosphatidylserine exposure in cells may enforce the interest for these findings.

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Thymosin α1 is a native peptide in several tissues

Cited by 36 publications

References 17 publications

Prothymosin α Is Processed to Thymosin α1 and Thymosin α11 by a Lysosomal Asparaginyl Endopeptidase

Prothymosin α Is Processed to Thymosin α1 and Thymosin α11 by a Lysosomal Asparaginyl Endopeptidase

A 180-kDa Protein Kinase Seems to Be Responsible for the Phosphorylation of Prothymosin α Observed in Proliferating Cells

New studies about the insertion mechanism of Thymosin α1 in negative regions of model membranes as starting point of the bioactivity

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